Focusing and Collimating - Newport
Focusing a Collimated Laser Beam. As a first example, we look at a common application, the focusing of a laser beam to a small spot. The situation is shown in Figure 1. Here we have a laser beam, with radius y 1 and divergence θ 1 that is focused by a lens of focal length f. From the figure, we have θ2 = y1/f.